“This is well beyond legal behaviour. We have asked the British government to intervene at a diplomatic level but also to provide protection for our vessels,” Barrie Deas, head of Britain’s fishermen’s organisations, told BBC radio.

British environment minister Michael Gove said the UK boats were fishing legally.

He told BBC Television: “We can insist that the French, because they have a legal responsibility to ensure that we don’t have scenes like those we saw earlier this week, ensure that those waters — their territorial waters — are appropriately policed so that legal fishing activity can continue.”

The head of Normandy’s fishing organisation Dimitri Rogoff said the attack was spontaneous but acknowledged events spiralled out of control. He said he deplored the violence.

“There should not be any brawling, that could end badly. Our main UK counterpart has proposed we hold talks quickly in France; we’ll receive a UK delegation in the coming days,” Mr Rogoff said on Wednesday.

Scallops – known as "Coquille Saint Jacques" in France – are one of just a few species whose catch is governed by national rather than European Union regulation.

France bans all scallop dredging between May 15 and October 1, but Britain allows its vessels to operate year-round.

While British ships have no access to French territorial waters up to 22 kilometres off the coast, they can legally operate in the expansive Baie de Seine that stretches from Cherbourg to Dunkirk.

After the row – dubbed the "Scallop Wars" – flared up five years ago, French and UK fishermen brokered annual agreements in which British fishermen limit their scallop dredging in the Baie de Seine in exchange for some French scallop permits.

“But in the past two years, we feel our British partners do not want to negotiate, maybe because of Brexit,” Mr Rogoff said.

He said the root of the problem is different economic models. Normandy fishermen, he said, operate mainly small family-owned boats close to their own shores and sell the scallops live. The British fleet, he said, included company-owned “floating factories” which freeze and process the catch onboard.

French fishermen argue that scallops should not be harvested in summer, when they reproduce.

“If everybody dredges for scallops all year round, soon there will be none left,” Mr Rogoff said.